This invention has to do with apparatus for the generation and recovery of heat from highly aromatic, generally refractory carbonaceous fuel reactants, particularly from coals and residual oils. Such fuel reactants may be "char" derived from pyrolysis or other rigorous treatment of bituminous, or sub-bituminous coals or heavy crude oil residue feedstocks, or be anthracite coals or like materials typically characterized by being predominantly carbon i.e. carbonaceous and predominantly aromatic rather than aliphatic in their carbon structure and generally refractory i.e. highly resistant to thermal decomposition.
More particularly, the invention relates to apparatus highly advantageous for obtaining maximum heat from such fuel reactants for production of steam useful e.g. for power turbines, while simultaneously precluding the release of atmospheric contaminants, particularly NO.sub.x, and reducing the size and complexity of capital equipment relative to conventional heat and steam generation facilities, and with minimum heat loss. In general, the invention involves significant breakthroughs in the generation of heat from the mentioned fuel reactants and numerous innovations in the handling of such heat for maximum benefit at minimum cost.
At the outset it must be mentioned that the apparatus operation is readily conducted at relatively low temperatures i.e. less than 1000.degree. C., temperatures below those at which significant formation of nitrogen oxides takes place. Thus the invention achieves the long sought goal of efficient conversion of e.g. coal to heat, without concomitant atmospheric contamination. In particular embodiments the use of nitrogen containing gases such as air is avoided, by the use, instead, of solid oxidizers such as metal bearing ores, but in all embodiments low reaction temperatures, possible through catalytic action and solution reaction occurring in the apparatus, enable efficient combustion of fuel reactant without substantial co-production of NO.sub.x.